Flows graphs should have a single entry point.

Multiple terminating junctions reduce readability of a flow graph.

This guideline ensures that execution of a flow graph always reaches the termination point.

This guideline ensures that unintended backtracking behavior does not occur in a flow graph. If unintended backtracking occurs during simulation, a warning message appears.

Unintended backtracking can occur at a junction under these conditions:

• The junction does not have an unconditional transition path to a state or terminating junction.

• Multiple transition paths lead to that junction.

Flow graphs test transitions, but do not execute them (and, therefore, never execute transition actions).